1. Field of the Invention
The present invention relates to a socket for an electrical part for detachably accommodating an electrical part such as a semiconductor device (hereinafter referred to “IC package”), and more particularly, a socket for an electrical part having a latch member to hold down (to press) the electrical part accommodated on the socket.
2. Description of the Related Art
As shown in FIGS. 15 and 16, a conventional IC socket 1 is known as a “socket for electrical parts” of this kind, which can accommodate IC package (not shown) as an “electrical part.”
The IC socket 1 comprises a socket body 2 having a base portion 3; a floating plate 4 disposed on a base portion 3 and urged upward by a spring 5, a floating plate 4 being vertically movable; and a plurality of spring-like contact pins 6 provided for the base portion 3 in a matrix-like arrangement, an upper end portion 6a of a contact pin 6 being inserted into a through hole 4a of the floating plate 4.
Oppositely provided at a right and left portion of the socket body 2 are a pair of latch members 7, which are each attached rotatably to the socket body 2 through rotational shafts 7a. The latch member 7 is urged by a torsional coil spring 8 toward an opening direction thereof.
In addition, on the socket body 2, an operation member 9 is provided and guided vertically by a guide pin 2a. The operation member 9 is urged upwardly by a coil spring 10.
Furthermore, the latch member 7 is engaged with an engaging shaft 9a provided on the operation member 9. The engaging shaft 9a is structured to rotationally move the latch member 7 in a closing direction thereof against an urging force of the torsional coil spring 8, when the operation member 9 is moved upwardly.
In such a socket mentioned above, when the operation member 9 is moved downwardly, the latch member 7 is rotationally moved to open by the urging force of the torsional coil spring 8 and then the IC package is accommodated on the floating plate 4. Then, with the operation member being moved upwardly, a rear end portion 7b of the latch member 7 is pushed up by the engaging shaft 9a of the operation member 9. And at the same time, a front end portion 7c of the latch member 7 pushes an upper surface of the IC package, thereby electrically connecting each of a plurality of terminals provided on a lower surface of the IC package with each of the contact pins 6.
However, in such a conventional socket mentioned above, the latch member 7 must be retracted from a region into which the IC package is inserted, in order to accommodate the IC package. Therefore, there have been a problem that it is necessary to secure a space for rotational movement of the latch member 7 and also to make the amount of vertical movement of the operation member 9 larger because the amount of the rotational movement of the latch member 7 must be made larger.
Furthermore, the front end portion 7c of the latch member 7 presses the IC package by making use of the “principle of leverage,” that is, by pressing the rear end portion 7b of the latch member 7 with the engaging shaft 9a of the operation member 9, therefore the distance L between a center of rotation of the latch member 7 and the rear end portion 7b becomes longer consequently, resulting in making the entire size of the IC socket 1 larger, being inconvenient.